Miniature diaphragm relay



Sept. 16, 1969 Filed Jan. 5, 1967 FIG. I.

2 Sheets-Sheet 1 I nvenlor A Horney p 1969 H. s. WOODHEAD 3,467,923

MINIATURE DIAPHRAGM RELAY Filed Jan. 5, 19s? 2 Sheets-Sheet 2 United. States Patent Int. Cl. H01h 1/12 US. Cl. 335-196 13 Claims ABSTRACT OF THE DISCLOSURE A miniature relay having changeover contacts for use in cross-point switches. The movable element of the relay is a resilient diaphragm mounted on an annular support member and normally in contact on one side thereof with a rod which forms a contact and being capable of being energized to make contact with a rod on the other side thereof. The diaphragm is slotted so that its central contact-making area is connected by two or more curved tongues to its periphery, increasing the resiliency of the diaphragm without appreciably increasing the reluctance of the magnetic circuits of which it forms part. Approximate dimensions are 0.40 inch in diameter and 0.6 inch in length.

The invention relates to electromagnetic contact-making relays and is an improvement in or modification of the invention described in US. Patent No. 3,331,040.

According to the invention such a relay includes an outer magnetic member, an inner magnetic member passing through an aperture in the outer magnetic member and electrically and magnetically insulated therefrom, and a resilient diaphragm of magnetic material in contact at its periphery to the outer magnetic member and normally spaced from the inner magnetic member on one side thereof and normally in contact on the other side thereof with a contact of the relay, said contact being electrically and magnetically insulated from said inner magnetic member and outer magnetic member the diaphragm and the inner magnetic member constituting the other contacts of the relay and being capable of being brought into contact with each other by the energisation of a magnetic circuit that includes the said inner and outer magnetic members and the diaphragm.

Other features of the invention will be evident from the following description of a preferred form of electromagnetic relay embodying the invention. The description refers to the accompanying drawings in which:

FIG. 1 shows a side view of the relay which is shown in part in longitudinal section along the centre line, and

FIG. 2 shows a plan view of the diaphragm of the relay.

The relay shown in the drawing is built upon a composite seal assembly comprising two mild steel annuli and 11, separated by a mild steel yoke 12 and each annuli having a nickel-iron cylindrical member 13 and 14 secured within their central aperture by an annular insulating seal 15, for example, of glass. The annulus 10, yoke 12 and cylindrical member 13 form part of the magnetic circuit of the relay and the annular end face 20 of the cylindrical member 13 also forms one of the cooperating contacts of the relay. The moving contact of the relay is formed by a resilient diaphragm 16 which rests at its periphery on the yoke 12, to be normally in intimate contact in a stressed condition with the other cooperating contact of the relay formed by the annular end faces 18 of the cylindrical member 14, such that there remains a suitable isolating gap between the central contact making area of the diaphragm and the cooperating end face 20 of the cylindrical member 13. The inner portion 19 of the yoke 12 serves to increase the magnetic field between the annulus 10 and tube 13 and lies below the level of the end face 20 of the cylindrical member such that on energization of the relay the diaphragm may freely move across the isolating gap.

It will be seen that the diaphragm 16 and the end faces 20 and 18 of the cylindrical members 13 and 14 are contained in a sealed enclosure, and that the major operation involved in making the enclosure, the sealing of the cylindrical member 13 within the annulus 10 and the cylindrical member 14 within the annulus 11 can be performed as the first manufacturing step in the construction of the relay so that the relatively high sealing temperature required cannot affect items such as the diaphragm or the relay winding which are added at a later stage. The annuli 10 and 11 can be secured to the yoke 12 by low temperature soft soldering.

The diaphragm 16 is provided with a number of slots 21- (FIG. 2), of length much greater than their width, that serve to increase the resiliency of the diaphragm and thus to reduce the stress necessary to distort it to make contact with the cooperating contact surface 20. The slots 21 are in the form of arcs of circles and are so interconnected that the central contact making area 22 of the diaphragm is connected with its peripheral area 17 by which it engages to the yoke 12 by three tongues of metal 23 of width small relative to their length. This arrangement allows the central area of the diaphragm considerable freedom of movement while at the same time ensuring that when it is attracted to the cylindrical member 13 by energization of the associated magnetic circuit it moves substantially normally into contact with the end face of the cylindrical member.

The diaphragm 16 must, of course, be made of a magnetic material such as a nickel-iron alloy, and in order to provide a good electrical contact it may be plated over all or part of its area with a suitable metal such as palladiumv A similar layer may be plated on to the end plate 20 of the cylindrical member 13. Besides forming the contact surface the protective layer or layers also provide the necessary magnetically insulating spacer between the contact members.

The cylindrical member 13 forming the inner magnetic member is considerably longer in the axial direction than the corresponding outer magnetic member formed by the annulus 10, the projecting part of the cylindrical member being surrounded by the operating winding 24 of the relay which is surrounded by an insulating cover 25 and wound on an insulating former 26. The outside diameter of the winding 24 and the former 26 is made not greater than the outside diameter of the annulus 10. An insulating washer 27 separates the spool assembly 28 and end plate 30 of magnetic material. The magnetic circuit is completed by an outer cover 31 of magnetic material which is sprung into position over the annulus 10 and the end cap 30. An insulated cover 32 may be provided on the annulus 11 to prevent short circuiting between the cylindrical member 14 and annuli 11 by foreign bodies and contact of the terminal 34 with the annulus 10.

The terminals of the relay consist of contact pins projecting from the curved surface of the relay assembly. The spacing of the pins may be such as to comply with the normal track spacings for printed circuit assemblies, the small physical dimensions of the relay (a practical realization being approximately 0.6 inch long and 0.4 inch in diameter) rendering it particularly suitable for such applications. The coil terminals of the relay are formed by pins 33 (one not shown) projecting from the coil former 26, while the break contact terminal is formed by a pin 34 projecting from the cylindrical member 14, the make contact terminal formed by the pin 35 projecting from the cylinder member 13 and the moving contact terminal formed by the pin 36 projecting from the annulus 10.

On energization of the coil 24 the diaphragm 16 is attracted to the contacts 20 of the cylindrical member 13, thereby forming a continuity of circuit between the make contact terminal 35 and the moving contact terminal 36. When the relay is in a de-energized state the diaphragm reverts to its less stressed position in contact with the contacts 18 of the cylindrical member 14 so providing a continuity of circuit between the break contact terminal 34 and the moving contact terminal 36.

It is to be understood that the foregoing description of specific examples of this invention is not to be considered as a limitation of its scope.

What is claimed is;

1. An electromagnetic contact-making relay including a first outer magnetic member, a first inner magnetic member passing through an aperture in the outer magnetic member and electrically and magnetically insulated therefrom, a second outer magnetic member, a second inner magnetic member passing through an aperture in the second outer magnetic member and electrically and mag netically insulated therefrom, a resilient diaphrgm of magnetic material, support means supporting said resilient diaphragm in electrical contact at its periphery to the first and second outer magnetic members, said support means normally holding the diaphragm in spaced relationship from the inner magnetic member and on one side thereof, the second magnetic. member including a face forming a first contact for the relay, said support means causing said resilient diaphragm to form a first contact pair in cooperation with said first contact of the relay, and the diaphragm and the first inner magnetic member constituting a second contact pair for the relay and being capable of making contact with each other by the energization of a magnetic circuit, where said magnetic circuit includes the said inner and outer magnetic members and the diaphragm.

2. A relay according to claim 1 wherein said inner members on either side of said diaphragm have physically identical contact areas and lie on the same longitudinal axis.

3. A relay according to claim 2 wherein said inner members on either side of the diaphragm are physically identical.

4. A relay according to claim 1 wherein'said outer members on either side of said diaphragm are physically identical and are coaxial about the longitudinal axis of said inner members.

5. A relay according to claim 4 wherein said outer 4 members on either side of said diaphragm are in contact with and separated by an' electrically and magnetically conducting member which is in contact with the periphery of said diaphragm.

6. A relay according to claim 5 wherein said member which separates said outer members is coaxial with said outer members about the longitudinal axis of said inner members.

7. A relay according to claim 6 wherein the diaphragm has therein two or more apertures situated between its peripheral and contact making areas and so formed that their presence reduces the stress necessary to cause the diaphragm to make contact with said inner magnetic member.

8. A relay according to claim 7 wherein the said apertures are slots of width small relative to their length.

9. A relay according to claim 7 wherein the said apertures are so formed that the contact making area of the diaphragm is connected with its peripheral area by two or more tongues of width small relative to their length.

10. A relay according to claim 9 wherein at least the contact making areaof the diaphragm has thereon a layer of a noble metal.

11. A relay according to claim 9 wherein the said inner magnetic member not normally in contact with said diaphragm extends beyond the said corresponding outer magnetic member on one side thereof and is surrounded by an operating winding of the relay.

12. A relay according to claim 11 including an end plate of magnetic material on the side of the operating winding remote from said outer magnetic member and a cover of magnetic material joining the end plate and said outer magnetic member and at least partly enclosing the winding, the end plate and cover forming a magnetically conductive but electrically insulating path between said outer magnetic member and the remote end of said inner magnetic member.

13. A relay according to claim 2 wherein the contact making surfaces of the inner members have the form of a plain annulus.

References Cited UNITED STATES PATENTS 3,331,040 7/1967 Woodhead 335196 FOREIGN PATENTS 1,399,005 4/ 1965 France.

BERNARD A. GILHEANY, Primary Examiner H. BROOME, Assistant Examiner 

